From: Peichen Huang <PeiChen.Huang@xxxxxxx>
[WHY]
We see unstable DP LL 4.2.1.3 test result with dpia pre-train. It is
because the outbox interrupt mechanism can not handle HPD
immediately and require some improvement.
[HOW]
1. not enable link if hpd_pending is true.
2. abort pre-train if training failed and hpd_pending is true.
3. check if 2 lane supported when it is alt mode
Reviewed-by: Wenjing Liu <wenjing.liu@xxxxxxx>
Reviewed-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@xxxxxxx>
Signed-off-by: Peichen Huang <PeiChen.Huang@xxxxxxx>
Signed-off-by: Tom Chung <chiahsuan.chung@xxxxxxx>
---
.../amd/display/dc/dio/dcn31/dcn31_dio_link_encoder.c | 5 +++--
drivers/gpu/drm/amd/display/dc/link/link_dpms.c | 9 +++++++++
.../amd/display/dc/link/protocols/link_dp_capability.c | 8 ++++++++
3 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dio/dcn31/dcn31_dio_link_encoder.c b/drivers/gpu/drm/amd/display/dc/dio/dcn31/dcn31_dio_link_encoder.c
index b2cea59ba5d4..9a92f73d5b7f 100644
--- a/drivers/gpu/drm/amd/display/dc/dio/dcn31/dcn31_dio_link_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dio/dcn31/dcn31_dio_link_encoder.c
@@ -653,8 +653,9 @@ void dcn31_link_encoder_get_max_link_cap(struct link_encoder *enc, struct dc_lin
if (!query_dp_alt_from_dmub(enc, &cmd))
return;
- if (cmd.query_dp_alt.data.is_usb &&
- cmd.query_dp_alt.data.is_dp4 == 0)
+ if (cmd.query_dp_alt.data.is_dp_alt_disable == 0 &&
+ cmd.query_dp_alt.data.is_usb &&
+ cmd.query_dp_alt.data.is_dp4 == 0)
link_settings->lane_count = MIN(LANE_COUNT_TWO, link_settings->lane_count);
return;
diff --git a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
index b8cfeb98e229..ec7de9c01fab 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
@@ -2548,6 +2548,15 @@ void link_set_dpms_on(
if (pipe_ctx->stream->dpms_off)
return;
+ /* For Dp tunneling link, a pending HPD means that we have a race condition between processing
+ * current link and processing the pending HPD. If we enable the link now, we may end up with a
+ * link that is not actually connected to a sink. So we skip enabling the link in this case.
+ */
+ if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA && link->is_hpd_pending) {
+ DC_LOG_DEBUG("%s, Link%d HPD is pending, not enable it.\n", __func__, link->link_index);
+ return;
+ }
+
/* Have to setup DSC before DIG FE and BE are connected (which happens before the
* link training). This is to make sure the bandwidth sent to DIG BE won't be
* bigger than what the link and/or DIG BE can handle. VBID[6]/CompressedStream_flag
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
index d0fbf9c44a29..44c3023a7731 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
@@ -2312,6 +2312,14 @@ bool dp_verify_link_cap_with_retries(
} else {
link->verified_link_cap = last_verified_link_cap;
}
+
+ /* For Dp tunneling link, a pending HPD means that we have a race condition between processing
+ * current link and processing the pending HPD. Since the training is failed, we should just brak
+ * the loop so that we have chance to process the pending HPD.
+ */
+ if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA && link->is_hpd_pending)
+ break;
+
fsleep(10 * 1000);
}
--
2.34.1
